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The Journal of Physical Chemistry. A Mar 2019Gas phase, isolated monosaccharides arabinose- and mannose-related anionic species generated through the matrix-assisted laser desorption ionization (MALDI) method are...
Gas phase, isolated monosaccharides arabinose- and mannose-related anionic species generated through the matrix-assisted laser desorption ionization (MALDI) method are investigated via negative ion photoelectron spectroscopy (PES) and density functional theory (DFT) calculations. The vertical detachment energies (VDEs) of the observed anionic species are experimentally determined: the corresponding structures are assigned based on good agreement between experimental and theoretical VDEs. Arabinose parent anion is found to exist as open chain structures in the gas phase, while mannose parent anionic species are not observed. Both monosaccharides undergo dissociation through loss of H and loss of HO. (saccharide-H) anions evidence coexisting positional and conformational isomers. (saccharide-HO) species have only two positional isomers, each with conformational differences. The present results for arabinose and mannose are further compared to those previously reported for ribose and fructose. This comparison is based on the anions observed and identified through the same PES/DFT techniques for the four saccharides (arabinose, mannose, ribose, and fructose). The issue of natural selection of ribose as the sugar backbone constituent of RNA is thereby explored from the point of view of anionic electronic structure and stability of the four species. Saccharide phosphates are also discussed in the present work with regard to addressing the unique natural selection of ribose for the backbone support of RNA and DNA.
Topics: Anions; Arabinose; Density Functional Theory; Fructose; Mannose; Models, Chemical; Molecular Conformation; Photoelectron Spectroscopy; Ribose; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 30807168
DOI: 10.1021/acs.jpca.8b11838 -
The Analyst Apr 2023Differentiation of stereoisomers that are only dissimilar in the orientation of chemical bonds in space by mass spectrometry remains challenging. Structural...
Differentiation of stereoisomers that are only dissimilar in the orientation of chemical bonds in space by mass spectrometry remains challenging. Structural determination of carbohydrates by mass spectrometry is difficult, mainly due to the large number of stereoisomers in carbohydrates. Arabinose and xylose are pentose stereoisomers typically present in plant polysaccharides and exist in α- and β-anomeric configurations of furanose and pyranose forms. Conventional methods used to determine the structures of polysaccharides include hydrolysis of polysaccharides into oligosaccharides followed by identification of these oligosaccharides' structures individually through nuclear magnetic resonance spectroscopy (NMR). Although the sensitivity of mass spectrometry is much higher than that of NMR, conventional mass spectrometry provides only limited useful information on oligosaccharide structure determination, only the linkage positions of glycosidic bonds. In this study, we demonstrated a mass spectrometry method for the identification of linkage positions, anomeric configurations, and monosaccharide stereoisomers of intact oligosaccharides consisting of arabinose and xylose. We separated arabinose and xylose monosaccharides into α-furanose, β-furanose, α-pyranose, and β-pyranose forms through high-performance liquid chromatography and obtained the corresponding collision-induced dissociation mass spectra. Using these monosaccharide spectra and a flow chart consisting of the proper CID sequences derived from the dissociation mechanisms of pentose, a simple multi-stage tandem mass spectrometry method for structural identification of intact oligosaccharides consisting of arabinose and xylose was developed. The new mass spectrometry method provides a simple method for determining the structure of polysaccharides consisting of arabinose and xylose. The flow chart can be used in computer coding for automation, an ultimate goal for oligosaccharide structure determination.
Topics: Tandem Mass Spectrometry; Pentoses; Arabinose; Xylose; Oligosaccharides; Polysaccharides
PubMed: 36929945
DOI: 10.1039/d3an00068k -
Frontiers in Immunology 2022Arabinogalactan (AG) participates in forming the cell wall core of mycobacteria, a structure known as the mAGP complex. Few studies have reported the virulence of...
Arabinogalactan (AG) participates in forming the cell wall core of mycobacteria, a structure known as the mAGP complex. Few studies have reported the virulence of inartificial AG or its interaction with the host immune system. Using clustered regularly interspaced short palindromic repeats interference gene editing technology, conditional mutants were constructed with a low expression of or (EmbA_KD or GlfT2_KD), which are separately involved in the biosynthesis of AG arabinose and galactose domains. High-performance gel permeation chromatography and high-performance liquid chromatography assays confirmed that the EmbA_KD strain showed a remarkable decrease in AG content with fragmentary arabinose chains, and the GlfT2_KD strain displayed less reduction in content with cut-down galactose chains. Based on transmission and scanning electron microscopy observations, the cell walls of the two mutants were found to be dramatically thickened, and the boundaries of different layers were more distinct. Phenotypes including the over-secretion of extracellular substances and enhanced spreading motility with a concomitant decreased resistance to ethambutol appeared in the EmbA_KD strain. The EmbA_KD and GlfT2_KD strains displayed limited intracellular proliferation after infecting murine J774A.1 macrophages. The disease progression infected with the EmbA_KD or GlfT2_KD strain significantly slowed down in zebrafish/murine tail infection models as well. Through transcriptome profiling, macrophages infected by EmbA_KD/GlfT2_KD strains showed enhanced oxidative metabolism. The cell survival measured using the CCK8 assay of macrophages exposed to the EmbA_KD strain was upregulated and consistent with the pathway enrichment analysis of differentially expressed genes in terms of cell cycle/apoptosis. The overexpression of C/EBPβ and the increasing secretion of proinflammatory cytokines were validated in the macrophages infected by the EmbA_KD mutant. In conclusion, the AG of appears to restrain the host innate immune responses to enhance intracellular proliferation by interfering with oxidative metabolism and causing macrophage death. The arabinose chains of AG influence the virulence and pathogenicity to a greater extent.
Topics: Animals; Arabinose; Galactans; Galactose; Immunity, Innate; Mice; Mycobacterium marinum; Virulence; Zebrafish
PubMed: 36090984
DOI: 10.3389/fimmu.2022.879775 -
International Journal of Biological... Dec 2022The ultrasonic-assisted extraction of polysaccharides from Camellia fascicularis (PCF) was optimized using response surface methodology. After separation and...
The ultrasonic-assisted extraction of polysaccharides from Camellia fascicularis (PCF) was optimized using response surface methodology. After separation and purification with DEAE-52 cellulose and Sephadex G-200 glucan gel columns, the purified polysaccharide components of PCFa-1 and PCFc-1 were analyzed for their structural characterization, antioxidant and anti-tumor activities in vitro. The results indicated that liquid to material ratio of 42 mL/g, ultrasonic time of 53 min, ultrasonic temperature of 73 °C, and ultrasonic power of 215 W were the optimum extraction conditions for PCF with maximum yields (4.05 %). PCFa-1 and PCFc-1 contained 5.88 % and 9.58 % uronic acid content, with 7.53 and 108.91 kDa of average molecular weights, respectively. The PCFa-1 was mainly constituted of galactose, arabinose, and glucose, while PCFc-1 was primarily composed of arabinose, glucose, galacturonic acid, and rhamnose. Fourier transform infrared spectra revealed that PCFa-1 and PCFc-1 contained typical polysaccharide bands. Scanning electron microscopy showed that the surface of PCFa-1 and PCFc-1 were irregular and clumpy structures. Nuclear magnetic resonance showed that PCFa-1 and PCFc-1 were mainly α-glycosidic bond conformation. Furthermore, the PCFc-1 showed better antioxidant capacities than PCFa-1 against hydroxyl, DPPH, and ABTS radicals and exhibited more potent toxicity on A549 and HepG2 cells. These research results suggested that PCF, especially PCFc-1, possesses great potential as natural antioxidants and anti-tumor drugs.
Topics: Antioxidants; Camellia; Arabinose; Polysaccharides; Glucose
PubMed: 36152704
DOI: 10.1016/j.ijbiomac.2022.09.176 -
Molecules (Basel, Switzerland) Dec 2022The extraction, characterization and antioxidant activity of polysaccharides from leaves were investigated in the present study. Two purified polysaccharide fractions,...
The extraction, characterization and antioxidant activity of polysaccharides from leaves were investigated in the present study. Two purified polysaccharide fractions, CALP-1 and CALP-2, were isolated from crude leaf polysaccharides (CALP) by DEAE-52 cellulose chromatography and Sephadex G-100 column chromatography. The characteristics of CAL-1 and CALP-2 were determined by using High-performance Gel Permeation Chromatography (HPGPC), High-Performance Anion-Exchange Chromatography, HPAEC (HPAEC-PAD) and Fourier transform infrared spectroscopy (FTIR). CALP-1 with molecular weight of 11.20 KDa was comprised of Rhamnose, Arabinose, Galactose, Glucose, Xylose, Mannose and galacturonic acid in a molar ratio of 5.16:2.31:5.50:27.18:1.00:0.76:1.07. CAL-2 with molecular weight of 8.03 KDa consisted of Rhamnose, Arabinose, Galactose, Glucose, and galacturonic acid at a ratio of 1.38:3.63:18.84:8.28:1.45. FTIR revealed that CALP-1 and CALP-2 were acidic polysaccharides. The antioxidant activity of crude CALP, CALP-1 and CALP-2 was evaluated in vitro. The fraction CALP-2 was demonstrated to be of polysaccharide nature containing a large percentage of Galactose but no Xylose and Mannose. The antioxidant activity assays showed that CALP-1 and CALP-2 exhibited antioxidant and scavenging activities on hydroxyl and DPPH radicals in vitro. Compared with pure polysaccharide, crude CALP exhibited stronger anti-oxidant activities. These results will provide a better understanding of axillaris leaf polysaccharide and promote the potential applications of axillaris leaf polysaccharide in the pharmacological field and as a natural antioxidant.
Topics: Antioxidants; Galactose; Mannose; Rhamnose; Arabinose; Molecular Weight; Chromatography, Gel; Polysaccharides; Plant Leaves; Glucose
PubMed: 36558014
DOI: 10.3390/molecules27248881 -
Food Chemistry Feb 2023Water-soluble polysaccharides (WSP) were extracted from the pulp of litchi. Its main component was identified as arabinogalactan. The dominant monosaccharide...
Water-soluble polysaccharides (WSP) were extracted from the pulp of litchi. Its main component was identified as arabinogalactan. The dominant monosaccharide constituents were arabinose and galactose. Galactose and mannose accumulated at the end of storage. ATP, ADP and AMP levels declined with increasing pulp breakdown index. WSP depolymerized which was characterized by a decrease in its content and molecular weight, while its structure remained stable during storage. Polygalacturonase and pectate lyase (PL) were active at the early storage time, and β-galactosidase (GAL) and α-l-arabinofuranosidase followed thereafter. Except for some pectin methylesterase (LcPME), LcPL, LcGAL and LcPME gene expression was downregulated. It was deduced that depolymerization of polysaccharides was mainly caused by the rupture of the branched side chain and glacturonic acid backbone to smaller repeating units, and both cell wall-degrading enzymes and nonenzymatic factors, such as energy level, participated in the degradation of polysaccharides, and consequently pulp breakdown of litchi.
Topics: Litchi; Polygalacturonase; Arabinose; Water; Galactose; Mannose; Polysaccharides; Fruit; Monosaccharides; beta-Galactosidase; Adenosine Diphosphate; Adenosine Monophosphate; Adenosine Triphosphate
PubMed: 36150360
DOI: 10.1016/j.foodchem.2022.134289 -
Carbohydrate Polymers Mar 2021Two novel arabinose- and galactose-rich pectic polysaccharides, AELP-B5 (M, 4.25 × 10 g/mol) and B6 (M, 1.56 × 10 g/mol), were rapidly obtained from the leaves of...
Two novel arabinose- and galactose-rich pectic polysaccharides, AELP-B5 (M, 4.25 × 10 g/mol) and B6 (M, 1.56 × 10 g/mol), were rapidly obtained from the leaves of Aralia elata (Miq.) Seem. with anion resin and sequenced ultrafiltration membrane columns. The structural backbone and branched chains of AELP-B5 and B6 were preliminarily elucidated by mild acid hydrolysis with HILIC-ESI-MS/MS. The planar structures and spatial configurations were further identified using UPLC-QDa and GC-MS for compositions, Smith degradation and methylation analysis, FT-IR, NMR (H/C, DEPT, HSQC, HMBC, COSY, NOESY and TOCSY) and SEC-MALLS-RID. (1) AELP-B5 possessed →GalA→ as smooth regions (HG) and a repeating disaccharide moiety of →GalA→Rha→ as hairy regions (RG-I) with a 1:5 molar ratio, whereas AELP-B6 had a distinguishing 1:1 molar ratio between the HG and RG-I; (2) complex side chains were constituted of T-α-Araf, 1,3-α-Araf, 1,5-α-Araf, T-β-Galp, 1,3-β-Galp, 1,4-β-Galp, 1,6-β-Galp, 1,3,4-β-Galp and 1,3,4,6-β-Galp connected at C-4 of the rhamnosyl units in RG-I of AELP-B5 and B6; and (3) both possessed highly branched and compact coil conformations. The CCK-8 assay illustrated that AELP-B6 possessed higher cytotoxicity against HepG2 and HT-29 than that of AELP-B5. Surface plasmon resonance showed the binding affinity of AELP-B6 to galectin-3 (6.488 × 10 M) was about 10 times stronger than that of AELP-B5 (4.588 × 10 M). The above findings provide a molecular structure and bioactivity basis for future potential applications of AELP in the food and medical industries.
Topics: Antineoplastic Agents, Phytogenic; Arabinose; Aralia; Blood Proteins; Carbohydrate Sequence; Cell Survival; Dose-Response Relationship, Drug; Galactose; Galectins; HT29 Cells; HeLa Cells; Hep G2 Cells; Humans; Hydrolysis; Pectins; Plant Extracts; Plant Leaves; Polysaccharides; Protein Binding; Structure-Activity Relationship
PubMed: 33436169
DOI: 10.1016/j.carbpol.2020.117326 -
EcoSal Plus Dec 2022Very few labs have had the good fortune to have been able to focus for more than 50 years on a relatively narrow research topic and to be in a field in which both... (Review)
Review
Very few labs have had the good fortune to have been able to focus for more than 50 years on a relatively narrow research topic and to be in a field in which both basic knowledge and the research technology and methods have progressed as rapidly as they have in molecular biology. My research group, first at Brandeis University and then at Johns Hopkins University, has had this opportunity. In this review, therefore, I will describe largely the work from my laboratory that has spanned this period and which was carried out by 40 plus graduate students, several postdoctoral associates, my technician, and me. In addition to presenting the scientific findings or results, I will place many of the topics in scientific context and, because we needed to develop a good many of the experimental methods behind our findings, I will also describe some of these methods and their importance. Also included will be occasional comments on how the research community or my research group functioned. Because a wide variety of approaches were used throughout our work, no ideal organization of this review is apparent. Therefore, I have chosen to use a hybrid structure in which there are six sections. Within each of the sections, experiments and findings will be described roughly in chronological order. Frequent cross references between parts and sections will be made because some findings and experimental approaches could logically have been described in more than one place.
Topics: Humans; Arabinose; Learning; Technology; Operon
PubMed: 36519894
DOI: 10.1128/ecosalplus.ESP-0012-2021 -
Cell Host & Microbe Mar 2023The molecular understanding of host-pathogen interactions in the gastrointestinal (GI) tract of superspreader hosts is incomplete. In a mouse model of chronic,...
The molecular understanding of host-pathogen interactions in the gastrointestinal (GI) tract of superspreader hosts is incomplete. In a mouse model of chronic, asymptomatic Salmonella enterica serovar Typhimurium (S. Tm) infection, we performed untargeted metabolomics on the feces of mice and found that superspreader hosts possess distinct metabolic signatures compared with non-superspreaders, including differential levels of L-arabinose. RNA-seq on S. Tm from superspreader fecal samples showed increased expression of the L-arabinose catabolism pathway in vivo. By combining bacterial genetics and diet manipulation, we demonstrate that diet-derived L-arabinose provides S. Tm a competitive advantage in the GI tract, and expansion of S. Tm in the GI tract requires an alpha-N-arabinofuranosidase that liberates L-arabinose from dietary polysaccharides. Ultimately, our work shows that pathogen-liberated L-arabinose from the diet provides a competitive advantage to S. Tm in vivo. These findings propose L-arabinose as a critical driver of S. Tm expansion in the GI tracts of superspreader hosts.
Topics: Salmonella typhimurium; Arabinose; Salmonella enterica; Polysaccharides; Serogroup
PubMed: 36812913
DOI: 10.1016/j.chom.2023.01.017 -
Bioresource Technology Dec 2018Most of the crop plants contain about 30% of hemicelluloses comprising D-xylose and D-arabinose. One of the major limitation for the use of pentose sugars is that high... (Review)
Review
Most of the crop plants contain about 30% of hemicelluloses comprising D-xylose and D-arabinose. One of the major limitation for the use of pentose sugars is that high purity grade D-xylose and D-arabinose are yet to be produced as commodity chemicals. Research and developmental activities are going on in this direction for their use as platform intermediates through economically viable strategies. During chemical pretreatment of biomass, the pentose sugars were generated in the liquid stream along with other compounds. This contains glucose, proteins, phenolic compounds, minerals and acids other than pentose sugars. Arabinose is present in small amounts, which can be used for the economic production of value added compound, xylitol. The present review discusses the recent trends and developments as well as challenges and opportunities in the utilization of pentose sugars generated from lignocellulosic biomass for the production of value added compounds.
Topics: Arabinose; Biofuels; Fermentation; Pentoses; Sugars; Xylose
PubMed: 30217725
DOI: 10.1016/j.biortech.2018.08.042